1. Field
The present disclosure relates generally to the field of loudspeakers, and more particularly to the confinement of vibrations associated with a loudspeaker driver.
2. Related Art
There are numerous types of audio transducers or drivers for loudspeakers. A functionality of the driver is as a traditional direct radiator, which may include, for example, a moving voice coil immersed in a static magnetic field, coupled to a rigid diaphragm and a suspension system.
A motor system of a loudspeaker may include a permanent magnet, surrounded by steel parts that direct and shape the magnetic field. The loudspeaker may also include a voice coil, which may be a conductive wire (e.g., copper clad aluminum), sometimes referred to as a voice coil wire, wrapped around a non-conductive bobbin, sometimes referred to as a voice coil former. The voice coil former can provide mechanical stability and a platform for transmitting the coil force to the diaphragm.
The diaphragm is typically rigid and lightweight to move the air accurately, with minimized “break up” modes or other misbehavior. Ideally, the diaphragm exhibits perfectly pistonic motion. The diaphragm, sometimes referred to as a dome due to its shape, may be formed from aluminum or similar materials, or composites thereof, that exhibit high stiffness, low mass, and high deformation, thereby allowing deep shapes to be formed.
The suspension system generally provides the restoring force and maintains the coil in the correct position. The suspension allows for controlled axial motion, while largely preventing lateral motion or tilting that could cause the coil to strike the motor components. The stiffness vs. deflection of the suspension is carefully designed to match the force vs. deflection characteristics of the voice coil and motor system. The suspension may comprise a member formed from a polyurethane foam material or the like, and may be compressed into shape by heat and pressure in a mold. However, numerous problems arise when the suspension member is attached to the diaphragm. For example, the attachment of a suspension member with the diaphragm may permit spurious vibrations from the suspension system to be transmitted across the surface of the diaphragm, resulting in distortion and inaccuracies in the frequency response.
One known approach involves separating the diaphragm from the suspension member, and thereby isolating the diaphragm from high frequency vibrations in the suspension system. However, the loudspeakers associated with such approaches and designs can be difficult to manufacture, resulting in loudspeakers that are fragile and lacking in durability and reliability. Accordingly, there remains a need for a loudspeaker technology that isolates the diaphragm from vibrations associated with the suspension system, while being easy to manufacture, robust, and reliable.